1. Field of the Invention
The present invention relates generally to devices, such as packages and bags, for dispensing sterile fluids, but more particularly to such devices capable of being including an interior bag and an exterior bag capable of being pressurized to force the fluid contents of the interior bag from an ejection port.
2. Description of the Related Art
In the majority of surgical procedures there is a requirement to have a pressurized flow of sterile fluids to the surgical site for the purpose of irrigation, hydrodissection, cavity distention, and lavage. Some examples of the surgical procedures requiring pressurized flow are laparoscopy, arthroscopy, cytoscopy, endoscopic sinus surgery, thoracoscopy, urethroscopy nephroscopy, hysteroscopy, and all open surgical procedures that require irrigation.
In the past, this pressurized fluid flow has been accomplished by various means. Perhaps the simplest of the various means entails hanging a sterile fluid bag from an intravenous (IV) pole. The system typically included a fluid delivery conduit (e.g., a length of tubing), attached to the bag and a fluid delivery instrument. The bag is then hung at an elevation greater than the instrument used to deliver or otherwise dispense the fluid to enable the force of gravity and the mass of the fluid to establish the pressurized fluid flow through the tubing. A common drawback associated with these type systems is the inability to maintain a constant delivery pressure. That is, as the fluid would be dispensed through the conduit and delivery instrument, the overall mass of the fluid would decrease and thus the pressurized flow due to the force of gravity would also decrease. In many such instances it was generally known that not all of the fluid inside the sterile bag was delivered to the desired site. Thus the only means to increase the fluid flow pressure and flow rate of the fluid was to raise the bag to a higher elevation. An example of one such sterile fluid bag that is commercially available is bag sold under the trademark VIAFLEX. VIAFLEX bags are constructed of a plastic material and contain various sterile fluid solutions for medical uses.
With the development of endoscopic and minimal invasion surgical procedures, such as percutaneous procedures, there exists a need to develop a more sophisticated system to deliver the fluid to the various instruments designed to accept the pressurized fluid flow in order to insure constant fluid delivery at a uniform pressure. As a result, medical and health care workers devised or implemented a way of attempting to solve the pressure delivery problems associated with gravitational delivery of sterile fluids. Their solution to the problem was to wrap a pressure cuff (e.g., common pressurizable blood pressure monitoring device) around a VIAFLEX type bag and apply squeeze pressure directly to the external surface of the bag. While this type of delivery enabled the user to administer fluids to the delivery site with much higher pressure than gravity alone could provide, it was difficult to maintain a constant pressure and dispense the entire fluid content of the bag.
A more sophisticated system was devised to replace the pressure cuff. The sophisticated system is capable of releasing fluid under pressure by a mechanical device whereby a VIAFLEX type fluid bag is placed into a box-like device capable of squeezing the bag via two opposing doors for applying pressure to the external surface of the bag. These systems are known to be expensive, cumbersome to set up, and still experience some of the limitations associated with emptying the entire contents of the bag because the mechanical compression of the bag could fold fluid pockets in the bag, thereby trapping sterile fluid inside the bag.
U.S. Pat. No. 3,838,794 granted to Cogley, et al is directed to a package for storing and dispensing liquids, and perhaps more importantly, for the reintroduction of fluids back into the Cogley device after it is emptied. The ability for reintroduction of fluids into such a device is believed to be an undesirable trait because of the inherent possibility of introducing contaminants with the replacement fluid reintroduced into the Cogley bag invention. The Cogley device incorporates a dual bag system where an interior fluid-containing bag is enclosed within an outer bag. The outer bag is configured to be pressurized and cause the interior fluid-containing bag to compress. The interior fluid-containing bag, as well as the outer bag, has an access port in which the interior bag may be punctured by a spike in the nature of a hollow piece of tubing or cannula with a pointed end such that the fluid can flow through the tubing.
The Cogley invention provides lateral ribs for rigidity in order that his device does not trap fluid within the bag when the bag invention is nearly empty. The lateral ribs are applied to the inner bag component and enable the inner bag to maintain a substantially upright relationship with respect to the outer bag component. The Cogley device, therefore, is believed to be capable of dispensing the entire content of the inner bag by virtue of the lateral rib arrangement. The ribs, however, are believed to add considerable cost, among other things, to the manufacture of the Cogley invention when one considers the present cost of manufacturing a sterile fluid bag.
The Cogley bag does not provide a suitable means for even application of pressure to the bag surface and thus a consistent delivery of fluid at a relatively constant pressure is believed to unobtainable to a large degree with the Cogley device. For example, while the inner bag of the Cogley device might be stabilized vertically, its relative position is not always centered in the outer bag. Thus pressure introduced into the outer bag may apply and uneven fluid delivery pressure force to the from or the back of the bag and not necessarily uniform. Such uneven application of pressure is believed to affect the delivery of the fluid from the inner bag. A stabilized inner bag, if properly constructed, would be capable of administering the entire content of the fluid within the bag, and enable a constant uniform pressure to the front and back surfaces of the inner bag to drive the delivery of the fluid, as well as prevent the reintroduction of fluid to eliminate the possibility of introducing invisible contaminants bag into the inner bag. In addition, the Cogley device is believed to provide an ineffectual uniform sterile seal between the inner and outer bags because of the inherent ability of the inner bag to flop around inside of the outer bag prior to, during, and even after delivery of the fluid from the inner bag.
Accordingly, until now, a pressurized fluid flow bag having an exterior bag and a stabilized interior bag, enabling the fluid delivery pressure force to be more uniformly equalized over the entire surface of the inner bag and thus more evenly and efficiently distribute the fluid contained within the interior bag under a constant pressure has not been invented.